HDDB (HardDisk DataBase) is a file search tool that provides as-you-type results to search terms. The program quickly assembles a database of the drive contents on initial program-run and keeps this until another check is run (or a regular check is set in options). Since the program doesn't auto scan for changes on start-up, searches can be conducted on the previously saved data.

Additional features include lightning fast sorting, folder search panel, folder sizes (enabled in Tools - Options), thumbnail view, folder tree view, named searches, multiple instances, file listing export, and command-line support. Although the program doesn't do live updates, it can be set to auto-update on a timer (e.g. 5 minutes, daily, at startup, etc.)

Only functional on NTFS drives, but does not require admin privileges or trigger UAC prompts like similar programs. Does not search file internals.

Note: Main site offline, linking to Archive.org and Softpedia. Accessory files are also available (thanks Userfriendly).